Latch installation machine

ABSTRACT

A pair of adjacent, rotating turrets are indexed to stop at various assembly stations, spaced circumferentially about each turret. Four ring holders are mounted on one turret for holding split rings. Four iparts nests are mounted on the other turret for holding lock tabs and latches wich are to be inserted into the rings. A ring loader is positioned at one work station adjacent the first turret for loading a piston ring onto a ring holder. Located at work stations adjacent the second turret are a lock tab loader and a latch loader for loading lock tabs and a latch, respectively, into a parts nest. The two turrets then share a common work station at which a ring holder and a parts nest are in alignment. At this point, a lifter pushes the lock tabs and latch out of the parts nest and into engagement with the ring whereby assembly of the ring and latch is facilitated. A ring unloader is located at yet another work station adjacent the first turret for unloading the completed rings. A clearing station is located at a work station adjacent the second turret for clearing the parts nest of any lock tabs and/or latch which might be left in the parts nest as a result of a defective assembly.

United States Patent [191 [451 July 3,1973

Hardick et al.

- LATCH INSTALLATION MACHINE [75] lnventors: Alden Hardiclt; Alvin M. Martin;

- Delbert House, all of Muskegon,

Mich.

[73] Assignee: Questor Corporation, Toledo, Ohio [22] Filed: June 17, 1970 [21] Appl. No.: 153,941

[52] US. Cl. 29/208 F Primary ExaminerThomas I-l. Eager Attorney- Price, James A. Mitchell et al.-

[57] ABSTRACT A pair of adjacent, rotating turrets are indexed to stop at various assembly stations, spaced circumferentially about each turret. Four ring holders are mounted on one turret for holding split rings. Four iparts nests are mounted on the other turret for holding lock tabsand latches wich are to be inserted into the rings. A ring loader is positioned at one work station adjacent the first turret for loading a piston ring onto a ring holder. Located at work stations adjacent the second turret are a lock tab loader and a latchloader for loading lock tabs and a latch. respectively, into a parts nest. The two turrets then share a common work station at which a ring holder and a parts nest. are in alignment. At this point, a lifter pushes the lock tabs and latch out of the parts nest and into engagement with the ring whereby assembly of the ring and latch is facilitated. A ring unclearing station is located at a work station adjacent the I second turret for clearing the parts nest ofany lock tabs and/or latch whichmight be left in the parts nest as a result of a defective assembly.

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1 LATCH INSTALLATION MACHINE BACKGROUND OF THE INVENTION This invention relates to an assembly apparatus for placing a gap holding latch across the gap in a split ring. More specifically, it relates to the assembly of spacerexpander piston rings of the type disclosed in US. Pat. No. 3,472,521 (K. J. Nisper, et al.) issued Oct. 14, 1969.

Such expander rings serve the function of holding a pair of spaced rails tightly against a piston cylinder wall. The rails then serve to scrape oil off the walls of the cylinder. The spacer-expander ring is of open cross section to allow the drainage of oil back to the crankcase.

In order to function properly, this spacer-expander ring must hold the scraping rails tightly against the cylinder walls. This purpose will be foiled if the spacerexpander is not properly installed in the piston. Improper installation occurs because the ring must, of necessity, have a gap in its circumference in order to facilitate assembly over the piston. It is not uncommon for automotive workers to inadvertently allow the ends of the spacer-expander ring to overlap when assembling it into a piston. If the ends of the spacer-expander ring overlap instead of abut, they will fail to put any tension on the scraper rails. This results in excessive oil burning in the cylinder. Further, there will be a tendencyfor the overlapping end of the spacer-expander ring to score the cylinder walls.

Because of the location of these spacer-expander .rings in the finally assembled engine, it is very difficult to detect such an improperly installed spacer-expander ring inan assembled engine. Consequently, such im- Basically, it comprises a latch 12 which is slidably held in place in the ring by means of a pair of lock tabs l5,

one being located on either side of the gap in the ring.

One problem encountered with such rings is that they are extremely costly to manufacture. In the past, they could be assembled only by hand. This work is extremely tedious and results in a costly product.

SUMMARY OF THE INVENTION The present invention comprises an apparatus whereby such rings can be automatically assembled. The apparatus includes means for holding a ring and means for automatically loading the ring onto thering means for forcing the latch into engagement with the ring.

In the preferred embodiment, means are also provided for loading lock tabs onto the latch holding means. However, this is not. necessarily essential to the invention since it may be possible to design a ring and 2 latch which do not have to utilize lock tabs for holding the latch in the ring.

In another aspect of this invention, the ring holding means and latch holding means are each mounted on a separate rotatable turret positioned adjacent one another. Means for indexing the rotation of the turrets cause the ring holding means and the latch holding means to stop at various work stations spaced circumferentially about each of the turrets. Thus, at one work station positioned adjacent the first turret, the means for loading rings would act to load a ring onto the ring holding means. Similarly, a means positioned at a second work station adjacent the second turret would load a latch onto the latch holding means. The first and second turrets then share a third and common work station at which the ring holding means and the latch holding means come into alignment. Means for pushing the latch out of the latch holding means into engagement with the ring then effectuates a final assembly of the ring.

In order to facilitate a proper insertion of the latch into the ring, means are provided for maintaining a predetermined gap in the ring which is placed on the ring holding means. The latch holding means includes a pusher for pushing the latch out of the latch holding means when activated. When the latch holding means and the ring holding means are aligned, a means for activating the pusher causes the latch to be pushed into engagement with the ring, across the predetermined gap.

Yet another object of the invention is to provide means for positive control of component parts at all times. Thusfor example, one of the parts loading devices utilizes a punch which drives a part downwardly through a passageway while the pusher described above comes up to meet it. The part is held between the pusher and punch until both part and pusher are driven down into the parts holder.

In another aspect of the invention the ring loading means includes ameans for expanding the ring to create a gap which is about the same as or greater than the gap maintained 'by the gap maintaining means on the ring holding means. Means are provided for moving the expanded ring into engagement with the ring holding means.

Thus, the various related concepts encompassed by this invention are directed towards various phases of automation of an operation which heretofore has been accomplished only by hand. These and other objects and advantages of the invention will become apparent through reference to the written specification and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 8 is a sectional view taken along plane VIII- VIII of FIG. 7, showing the ring loader in its aft position;

FIG. 9 is a side elevation of the ring loader showing it in its forward position;

FIG. 10 is a plan view of the ring loader without its associated fingers;

FIG. 11 is a cross-sectional view taken along plane Xl-Xl of FIG. 8;

FIG. 12 is a cross section taken along plane XII-XII of FIG. 2, showing the drive system for ring loader;

. FIG. 13 is a front elevational view of the parts nest;

FIG. 14 is a plan view of the parts nest;

FIG. 15 is a cross section taken along plane XV-XV of FIG. 14, with a latch and lock tabs in place in the parts nest;

FIG. 16 is a front elevational view of the top portion of the pusher, which is an element of the parts nest assembly;

FIG. 17 is a plan view of the pusher;

FIG. 18 is a cross section taken along plane XVIII- --ZVIII of FIG. 17;

FIG. 19 is a cross section taken along plane XIX- XIX of FIG. 2, showing the lock tab loader;

FIG. 20 is a cross section taken along plane XXXX of FIG. 19, showing the plastic web stock feeder;

FIG. 21 is a side view of the web stock feeder in its feed cycle;

FIG. 22 is a side view of the web stock feeder in its retract cycle;

FIG. 23 is a cross section taken along plane XXIII- -XXIII of FIG. 19, showing the pushers meeting the lock tab punch;

FIG. 24 is a side elevation of the loader-lifter assemy;

FIG. 25 is a plan view of the loader-lifter assembly;

FIG. 26 is a cross section taken along plane XXVI- XXV.I of FIG. 25;

FIG. 27 is a cross section taken along plane XXVII- XXVII of FIG. 25;

FIG. 28 is a side elevation of the latch loader;

FIG. 29 is a side elevation of the assembly lifter in its down position;

FIG. 30 is a side elevation of the assembly lifter in its up position;

FIG. 31 is a fragmentary cross-sectional view of the jaw area of the parts nest in position beneath the ring locators of the ring holder, in alignment at work station 3.

FIG. 32 is the same view as FIG. 31, with the pushers of the parts nest being in an up position, pushing lock tab and latch into the ring;

FIG. 33 is a plan view of the ring unloader;

FIG. 34 is a front elevational view of the ring unloader;

FIG. 35 is a side elevational view of the ring unloader;

FIG. 36 is an elevated perspective view of the parts clearing assembly;

FIG. 37 is a generally side perspective view of the PREFERRED EMBODIMENT The purpose of latch installation machine 10 (FIG. 2) is to assemble a latch 12 and latch lock tabs 15 into a spacer ring 18 (FIG. 38). In order to accomplish this end, the various components are loaded onto appropriate parts holding devices, moved into alignment and then automatically assembled.

The components are moved from place to place by a pair of rotatable turrets, a ring turret 20 and a parts turret 30, which are mounted adjacent to one another (FIGS. 1 and 2). Mounted on ring turret 20 are four ring holders 60, each for holding a ring 18. Mounted on parts turret 30 are four parts nests 160, for holding the latches and the lock tabs. Rotation of ring turret 20 and parts turret 30 is indexed, such that the ring holders 60 and latch holders 160 are brought to a stop in alignment with various assembly stations spaced circumferentially about each turret'(FIG. 1). Various assembly components are positioned at these work stations for loading parts onto a ring holder 60 and parts nest 160, for effecting assembly of the components and for removing the assembled spacer ring and latch.

Located at work station 1 (FIG. 1), adjacent ring turret 20, is a ring loader (FIG. 2) which loads a ring 18 onto one of the ring holders 60. At the same time, a lock tab loader 220 (FIG. 2), located at work station 5 (FIG. 1) adjacent parts turret 30, loads apair of lock tabs 15 into parts nest 160. Turret drive 40 (FIG. 3) then rotates ring turret 20 and parts turret 30 through such that the loaded ring holder 60 is positioned in alignment with work station 2 (FIG. 1) and the previously loaded parts nest is located in alignment with work station 6.

No assembly component is located at work station 2. However, a latch loader 290 (FIG. 2) is positioned at work station 6 (FIG. 1) for loading a latch into parts nest 160. With this accomplished, turret drive 40 again rotates the two turrets through 90' such that the particular ring holder 60 and parts nest 160 under discussion now come into alignment with work station 3 (FIG. 1). Work station 3 is the assembly station and is common to both ring turret 20 and parts turret 30. At work station 3, the ring holder 60 and parts nest 160 are in alignment withone another. At this point, assembly lifter 310 is activated and acts in conjunction with pushers 171 in parts nest 160 to drive latch 12 and lock tabs 15 upwardly into engagement with ring 18, to thereby effectuate an assembly of the completed latched ring 11 (FIG. 38).

With assembly thus effected, both turrets are again rotated 90' by turret drive 40 and a ring unloader 340, positioned at work station 4, unloads the assembled, latched ring 11 from ring holder 60. Ring holder 60 is now empty and can again be loaded when it is rotated into alignment with work station 1.

Once assembly is effected at work station 3, parts nest 160 should also be empty. However, there always exists the possibility of an aborted assembly with the result that a latch 12 and/or one or both lock tabs 15 might remain in parts nest 160. To insure removal of such parts, a clearing apparatus 380 is positioned at work station 7 (FIG. 1), adjacent parts turret 30, to clear parts nest 160 of any parts remaining therein.

Upon rotation of the turrets another 90, the above cycle is again repeated with the same parts nest 160 and ring holder 60. Because there are four such parts TURRETS AND TURRET DRIVE Ring turret and parts turret are driven by an elaborate turret drive (FIG. 3). The prime mover of turret drive 40 is a DC motor 41 having a motor output shaft 42. Motor output shaft 42 is connected to a gear reducer 44 through a clutch brake assembly 43. Gear reducer 44 drives an indexing drive system 45.

Indexing drives are well-known in the art, and indexing drive 45 can be a conventional indexing drive train which will index the rotation of the shaft for 90 of rotation followed by a dwell time prior to subsequent rotation. One indexing drive which has been found suitable can be purchased from Ferguson Machine Company and bears their general designation of 8/2FM75-l20.

The principle of indexing drives 45 is illustrated schematically in the cut-away portion of FIG. 3. Thus, an output shaft 44a of gear reducer 44 drives a cylindrical cam 46. The track of cam 46 is open at each end such that it can pick up a follower 46a mounted on a vertical output shaft 48, carry follower 46a through a rotational period and a dwell time, and then discharge it out the other open end of the track and pick up yet another follower 46a. Since there are four work stations about each of the turrets 20 and 30, there are four such cam followers 46a on vertical output shaft 48.

Vertical output shaft 48 is connected to parts turret shaft 49 through atorque limiter 51. Torque limiter 51 operates on conventional principles, and comprises a pair of spaced plates 51a, one connected to vertical output shaft 48 and the other connected to parts turret drive shaft 49. The spaced plates 51a are operably connected through an interacting wedge 51b and slide 51c. A plurality of wedges 51b are mounted on the lower plate 51a while a plurality of slides 510 are mounted on the upper plate 51a. As long as parts turret drive shaft 49 does not meet with any resistance, it will be rotated by vertical output shaft 48 through the interaction of wedges 51b with slides 51c. However, as soon asany resistance is applied to shaft 49, as for example when parts turret 30 or ring turret 20 becomes jammed for some reason, output shaft 48 will continue to rotate while parts turret drive shaft 49 will stop rotating. Consequently, it will ride upwardly because of the action of slide 510 sliding on wedge 51b. As it 'does, itwill ev'entually comeinto contact with a ground contact 51d which sends a signal to brake clutch 43 ordering it to disengage and thereby brake the drive train from motor 41.

Parts turret 30 is secured directly to the top of parts turret drive shaft 49, the latter being journaled in a cylindrical housing'50. The rotation of parts turret drive shaft 49 is transferred to ring turret drive shaft 54 through a drive gear 52, connected to parts turret drive shaft 49, and .an output gear 53 connected to ring turret drive shaft 54. There is a one-to-one relationship between drive gear 52 and output gear 53 such that ring turret drive shaft 54 is rotated in a manner identical to the rotation of parts turret drive shaft 49. Ring turret drive shaft 54 is carried in a cylindrical housing 55 which is mounted adjacent cylindrical housing 50, both being mounted on a table 59. Ring turret 20 is mounted directly on top of ring turret drive shaft 54.

It is important that the rotation of ring turret 20 and parts turret 30 through 90 segments be very carefully controlled such that one does not rotate 89 while the other rotates 90". One factor which could interfere with this control would be sloppiness between drive gear 52 and output gear 53. To insure that such sloppiness does not result, a drag assembly 56 is operably connected to ring turret 20 and, accordingly, to ring turret drive shaft 54 to insure that the teeth of output gear 53 are always held tightly against the teeth of drive gear 52. Drag assembly 56 includes a mounting 57 which is secured to cylindrical housing 55. A spring steel plate 58 is secured and extends upwardly from mounting 57. Mounted on top of spring steel plate 58 is a fiberglass brake shoe 584 which engages a downwardly depending portion of ring turret 20. This downwardly depending portion has been designated as brake drum 21. Thus, brake shoe 58a applies a constant drag on brake drum 21 and accordingly on ring drive shaft 54.

7 As a result of the arrangement of components in turret drive 40, motor 41 will'be operating at all times. As long as brake clutch 43 is engaged, the cylindrical cam 46 of indexing drive 45 will constantly be rotating. However, due to the nature of such indexing drive systems, vertical output shaft 48 will be caused to rotate first through 90 and then to dwell, without rotating, for a period of time. This rotation is transmitted to ring turret 20 and parts turret 30 such that they repeatedly rotatethrough 90 and then dwell.'It is during this dwell time that assembly operations are performed at the various work stations spaced circumferentially about ring turret 20 and parts turret 30.

In the event of some type of jam, torque limiter 51 signals clutch 43 to disengage. This allows motor 41 to continue operating without causing damage to the rest of the drive train.

Finally, 'a constant tension is maintained between drive gear 52 and output gear 53 by means of a drag assembly 56 which acts upon ring turret 20 and accordingly on ring turret drive shaft 54.

RING HOLDER The function of the ring holder 60 (FIGS. 2 and s is to hold ring 18 in appropriate fixed position during transport and assembly. Ring 18 must be held with a predetermined distance across its gap in order to facilitate assembly with latch 12 and lock tabs 15. Thus, ring holder 60 includes magnets 63 for holding ring 18, gapper arrowhead 64 for maintaining an appropriate distance across the gap of ring 18, and locators 75 for holding ring 18 during assembly (FIG. 5).

Magnets 63 are mounted in a holder plate 61 (FIG. 5) which is securedto a mounting block 62 (FIG. 6). Mounting block 62 is then securely mounted on ring turret 20.

Arrowhead gapper 64 is shaped like an arrowhead, as is indicated by its name (FIG. 6). Slanting rearwardly and outwardly from its blunt nose, 65 are slanted sides 65a. These sides then become parallel and jut inwardly to shaft 67 to define a catch 68 at either side of shaft 

1. An apparatus for installing a latch across the ends of a split ring, said apparatus comprising: a first rotatable turret and a second rotatable turret positioned adjacent one another; means mounted on said first turret for holding a ring; means mounted on said second turret for holding a latch; means for rotating said turret; means indexing the rotation of said turret whereby said ring holding means and said latch holding means are stopped at various work stations spaced circumferencially about each of said turrets; means positioned at a first work station, adjacent said first turret for loading a ring onto said ring holding means when said ring holding means is aligned therewith; means positioned at a second work station, adjacent said second turret, for loading a latch onto said latch holding means when said latch holding means is aligned therewith; said first and second turrets sharing a third and common work station at which said ring holding means and said latch holding means come into alignment with one another; means at said third work station for forcing a latch out of said latch holding means into engagement with said ring on said ring holding means.
 2. The apparatus of claim 1 which comprises: means at a fourth work station adjacent said second turret for loading lock tabs onto said latch holding means; said fourth work station being positioned ahead of said second work station in the direction of rotation of said second turret whereby said lock tabs are loaded onto said latch holding means ahead of said latch; said forcing means at said third work station acting to push said lock tabs into engagement with said ring, behind said latch, whereby said latch is locked in place in said ring.
 3. The apparatus of claim 2 which comprises: means at a fifth work station, adjacent said first turret, for unloading completely assembled rings from said first turret; said fifth work station being behind said third work station in the direction of rotation of said first turret.
 4. The apparatus of claim 3 which comprises: means at a sixth work station, adjacent said second turret for clearing lock tabs and/or a latch from said latch holding means in the event that assembly is not achieved at said third work station; said sixth work station being positioned behind said third work station in the direction of rotation of said second turret.
 5. The apparatus of claim 1 in which said indexing means includes a drag acting against the rotation of said turret whereby positive positioning of saiD turrets is maintained.
 6. The apparatus of claim 1 which comprises: said ring holding means having a holder plate and a gapper projecting outwardly from said holder plate; said ring loading means including a fin member upon which a ring can be placed with its split ends on either side thereof; said fin member being telescopingly mounted in a loader member; means biasing said fin to a position projecting from said loader member; said gapper and said fin being positioned in alignment at said first work station; means operably connected to said load member for recriprocating said load member towards and away from said ring holding means; said loader member including means stationary with respect to said loader member for scraping a ring off of said fin onto said gapper as it is telescoped inwardly through contact with said gapper as said loader member is being reciprocated forwardly by said recriprocating means.
 7. The apparatus of claim 1 in which said ring holding means comprises a holder plate having magnets therein for retaining a ring against said holder plate; said holder plate having dimensions such that at least a portion of a ring is exposed in a fore-and-aft direction as it is held in position on said holder plate; ring unloading means being positioned at a fifth work station, adjacent said first turret, for unloading completely assembled rings from said first turret; said fifth work station being behind said third work station in the direction of rotation of said first turret; said ring unloading means including a kicker, means for reciprocating said kicker in a fore-and-aft direction, said kicker being positioned such that its path of travel passes through said exposed portion of a ring on said holder plate when said ring holding means is positioned at said fifth work station; a chute being positioned at said fifth work station at the end of the path of travel of said kicker for capturing a ring which is kicked free of said holder plate; a cone-shaped member positioned at the end of said chute for capturing a ring sliding off the end thereof.
 8. The apparatus of claim 7 in which said chute includes a flexible tab positioned above said chute and projecting downwardly to the surface of said chute for insuring that rings captured on said chute will lay flat as they slide down said chute.
 9. The apparatus of claim 8 in which a guard extends outwardly from the end of said chute for preventing rings sliding down said chute from over-shooting said cone positioned at the end of said chute.
 10. The apparatus of claim 1 which includes: a pusher slidably mounted in said latch holding means; said forcing means acting on said pusher to move said pusher towards said gapped ends of said ring and thereby force said latch into engagement with said ring; said ring holding means including a locator slidably mounted thereon for slidable movement into engagement with the gapped ends of said ring, to the outside of the circle defined by said ring; means positioned at said third work station for moving said locator into engagement with said ring just prior to the activation of said lifter means whereby said ring is firmly held in position when said latch is engaged into said ring.
 11. The apparatus of claim 10 in which: said latch holding means comprises a jaw; bias means at each side of said jaw to hold each end of said latch firmly in place within said jaw.
 12. The apparatus of claim 10 in which: said latch holding means is slidably mounted on a track member whereby said latch holding means can be moved upwardly into a position immediately beneath said split ring prior to upward movement of said pusher with respect to said latch holding means.
 13. The apparatus of claim 12 in which said pusher extends below said latch holding means and is pivotally connected to a rocker arm; said rocker arm being pivotally connected to said track member; bias means between the pusher end of said rocker arm and said latch holding means whereby said pusher and said latch holding means aRe biased to movement away from one another such that the application of a force to the base of the rocker arm near said pusher end thereof causes said latch holding means and said pusher to move upwardly simultaneously until said latch holding means contacts said ring, and then causes said pusher to move upwardly with respect to said latch holding means to push said latch out of said latch holding means and into engagement with said ring.
 14. The apparatus of claim 1 in which said means for loading a latch onto said latch holding means includes a punch for punching a latch from a web of plastic and for driving said latch downwardly into said latch holding means; means for advancing said web of plastic to said punch.
 15. The apparatus of claim 2 in which said means for loading lock tabs onto said latch holding means comprises: a first pair of spaced punches for punching lock tabs out of an advancing web of plastic material; a pair of return punches positioned directly below said first punches and being biased to upward movement whereby said lock tabs, after being punched out by said first punches, are returned to said plastic web by said return punches when said first punches retract from said plastic web; means for advancing said plastic web; a pair of loading punches positioned ahead of said first punches and said return punches for driving said lock tabs out of said plastic web in which they are carried and for carrying them downwardly into said latch holding means. 